Peripheral Arterial Bypass Grafts Research Articles

Tissue‐engineered vascular grafts for cardiovascular disease management: Current strategies, challenges, and future perspectives

AbstractCardiovascular diseases are the leading cause of mortality which primarily occurs due to the blood vessel obstruction or narrowing. Surgical procedures such as, coronary artery and peripheral artery bypass grafting frequently require vascular grafts for long‐term revascularization. However, using autogenous vessels, such as the internal thoracic artery and saphenous vein, especially for vessels with diameters less than 6 mm, are associated with number of concerns due to limited availability, invasive retrieval procedures, and aptness. To overcome these limitations, the development of tissue‐engineered vascular grafts (TEVGs) is in continuous thrust. This review comprehensively provides the potentiality of a range of artificial and naturally occurring biopolymers and their fabrication techniques, cell sources and seeding techniques to realize the state‐of‐the‐art TEVGs. Moreover, this review article presents a synopsis of insights obtained from a variety of in vitro and in vivo studies, including human clinical trials. It underscores the need for further exploration into key areas such as optimal cell sources, seeding techniques, mechanical properties, hemodynamics, graft integration, the impact of patient conditions, optimum burst pressure, sufficient suture strength, hydrophilicity, biodegradability, and related factors. In summary, the review offers insights into the current strategies, challenges, and future perspectives of TEVG.

Popliteal access for endovascular procedures in femoropopliteal artery occlusive disease.

Even though it has been reported that femoropopliteal artery endovascular revascularization is often performed with antegrade femoral artery interventions, which are technically relatively challenging, having the advantage of better control, it has also been reported that recanalization failure may occur in approximately 20% of patients and some materials have been developed for this reason. To evaluate the safety of retrograde popliteal artery intervention and our procedural success rate for symptomatic femoropopliteal artery occlusive disease. A total of 95 endovascular revascularization procedures were performed for treating symptomatic occlusive peripheral artery disease in the study period. Inclusion criteria were defined as patients who underwent endovascular revascularization procedures for symptomatic femoropopliteal artery occlusive disease. Patients who underwent a percutaneous endovascular procedure for iliac artery or below-knee arterial occlusive disease in the same session and patients who had previously undergone peripheral arterial bypass grafting or endovascular treatment for existing femoropopliteal artery disease were excluded. We evaluated 45 peripheral endovascular procedures performed on 39 patients with a mean age of 62.49 ±11.38 years in our hospital for chronic femoropopliteal artery occlusive disease. Twelve (26.7%) of the endovascular treatment procedures were performed with retrograde access through the popliteal artery (Group 2). In neither group were any complications of arterial rupture, distal embolism, early thrombosis, or pseudoaneurysms observed. We are of the opinion that the retrograde popliteal artery technique is an effective and safe intervention option in endovascular revascularization, particularly in the revascularization of the long segment and complex femoropopliteal artery occlusions.

Composite Porous Tubular Biopolymer Matrix of Small Diameter

One of the main problems in cardiovascular surgery is the lack of functionally reliable small-diameter (no more than 4 mm) vascular grafts required for coronary artery bypass grafting and peripheral artery and vein bypass grafting. The purpose of this work is the development of a composite biopolymer porous tubular matrix (CPTB matrix) 2 and 4 mm in diameter with adjustable resorption time and physicomechanical properties close to native blood vessels of the same diameter. The specimens of CPTB matrices with a diameter of 2 and 4 mm were produced by means of electrospinning from poly(hydroxybutyrate-co-hydroxyvalerate) and gelatin solution in hexafluoroisopropanol. The matrix structure was stabilized by treatment with glutaraldehyde (HA) vapor. It was demonstrated that the best specimen in terms of structure, physicomechanical properties, and resorption rate is the matrix obtained with the ratio of poly(hydroxybutyrate-co-hydroxyvalerate) : gelatin equal to 1 : 2 v/v in the solution and additionally crosslinked in HA vapor for 48 h. The detected slight cytotoxicity of the CBPT matrices developed is easily eliminated by treatment with an aqueous solution containing a set of amino acids. Decreasing the diameter of the substrate rod from 4 to 2 mm is accompanied by small changes in the surface structure and the physicomechanical properties of the CPTB matrix.

Evaluation of graft anastomosis using time-intensity curves and quantitative near-infrared fluorescence angiography during peripheral arterial bypass grafting.

Near-infrared fluorescence angiography (NIR) visualizes blood perfusion using the fluorescence property of indocyanine green (ICG). This study aimed to retrospectively determine the usefulness of a quantitative analysis using NIR to predict the patency of peripheral arterial bypass grafts by measuring their fluorescence luminance intensities (FLIs).Thirteen grafts in 11 patients who underwent peripheral arterial bypass grafting were divided into a patent graft group (n = 7) and a failed graft group (n = 6). The changes in the FLIs of ICG opacification through the graft and distal host artery were retrospectively analyzed using stored NIR data. The time-intensity curves (TICs) of ICG opacification through the graft (Qgraft) and distal host artery (Qdistal) were measured. Two parameters, Δ(Qgraft - Qdistal) and integral(Qgraft - Qdistal), were also analyzed.Although not significant, decreases in Qgraft were observed in the failed graft groups. The Qdistal of the failed graft group was significantly attenuated as compared with that of the patent graft group. Δ(Qgraft - Qdistal) increased only in the failed graft group, which indicates widening of the gap in FLI. Integral(Qgraft - Qdistal) was higher in the failed graft group, as it reflects the accumulation of ICG opacification.The TICs were influenced by anastomotic stenosis in the distal site of the host arteries. Our results indicate that the comparison of Δ(Qgraft - Qdistal) and integral (Qgraft - Qdistal) quantitatively analyzed using NIR can potentially predict anastomotic stenosis.

A Case of Anastomotic Stenosis of a Peripheral Arterial Bypass Graft Undetected in Indocyanine Green Angiography.

We report the case of a 75-year-old man who underwent right femoral-popliteal bypass surgery. Anastomotic stenosis was overlooked in indocyanine green (ICG) angiography due to opacification on the bypass graft. X-ray angiography revealed slit-shaped stenosis in the distal graft anastomosis that required revision. Although blood flow may be maintained despite of anastomotic stenosis, small decreases in blood flow cannot be detected in ICG angiography. We describe and discuss the pitfalls of qualitative graft assessment using ICG angiography, and compare ICG fluorescence luminance intensity between primary and revised grafts.

The impact of myogenic cell transplantation on collateral capillary arteriogenesis

Current treatments for peripheral arterial occlusive disease (PAOD), including angioplasty and bypass grafting fail in up to 25% of patients, or are not indicated in up to 50%, so there is a need to develop additional treatment options. Patients with native collaterals have a better prognosis, so a treatment such as cell transplantation that promotes collateral arteriogenesis is a potential PAOD treatment. Unfortunately, bone marrow derived stem cells, the main cell type that has been investigated, have limited clinical effectiveness in enhancing pre‐existing collateral growth. Therefore, delivering a stem cell type native to the collateral‐containing tissue, such as myogenic stem cells, could have improved outcomes. Additionally, about 20% of patients never develop collaterals, and no one, to our knowledge, has evaluated the effect of cell therapy on collateral capillary arteriogenesis (CCA), which can reperfuse ischemic tissue in animals without native arteriolar collaterals and therefore represents a potential therapeutic target in patients who lack native collaterals. To test the hypothesis that myogenic cells enhance CCA, we ligated the spinotrapezius feed artery in Balb/C mice to induce CCA, and delivered myogenic cells, thrombin (positive control), or vehicle to the muscle. Seven days post ligation, ‐‐‐‐arterialized collateral capillary (ACC) number and diameter were determined. As expected, thrombin increased ACC number, but myogenic cells had no effect, 9.3 ± 0.5 vs 7.1 ± 0.4, respectively. However, myogenic cells increased ACC diameter as compared to untreated (12.1 ± 0.8 μm vs 10.3 ± 0.3 μm, respectively) and both myogenic cells and thrombin increased the maximum ACC diameter (29.9 ± 3.4 μm and 27.9 ± 2.0 μm vs 18.8 ± 1.1 μm, respectively). These results are consistent with previous studies indicating that thrombin enhances arteriogenesis and suggest that myogenic cells have a similar effect, but likely without the deleterious pro‐inflammatory effects of thrombin. Because myogenic cells increase arteriogenesis and macrophages are an essential part of arteriogenesis, we also tested the hypothesis that myogenic cells increase macrophage content by performing CD68 staining. Although macrophage number increased following ligation, neither myoblasts nor thrombin further increased macrophage number. The lack of difference in macrophage number despite enhanced CCA could be because the day‐7 timepoint was too late, as macrophages peak around day‐3, or because a shift towards either classically‐activated macrophages or alternatively‐activated macrophages, which have a greater effect on arteriogenesis, would not be detected by the CD68 stain. Therefore, future studies may include a day‐3 timepoint and a stain for alternatively‐activated macrophages.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

B-Flow Imaging in Lower Limb Peripheral Arterial Disease and Bypass Graft Ultrasonography

Doppler ultrasonography plays a key role in the diagnosis of peripheral arterial disease, but is often limited by pitfalls that may be overcome by B-flow imaging. Thus far, there is little information on B-flow imaging for the assessment of peripheral arterial disease and bypass grafts in lower limbs. This article describes the authors' early experience with B-flow in the lower extremities. Sixty patients were included among a large cohort of patients routinely referred to the vascular laboratory for peripheral arterial disease and bypass graft assessments. Two experienced vascular sonographers performed all scans, comparing color Doppler ultrasonography with B-flow imaging. All scans were performed using a combination of the 9 L linear and C2-9 curvilinear transducers with the LOGIQ E9 system (GE Healthcare, Waukesha, WI, USA). Our experience indicates that this relatively unexplored technology has the potential to significantly improve peripheral blood flow evaluation. Nevertheless, B-flow imaging is not exempt from limitations and should be considered complementary to color Doppler ultrasonography.

The Tissue-Engineered Vascular Graft-Past, Present, and Future.

Cardiovascular disease is the leading cause of death worldwide, with this trend predicted to continue for the foreseeable future. Common disorders are associated with the stenosis or occlusion of blood vessels. The preferred treatment for the long-term revascularization of occluded vessels is surgery utilizing vascular grafts, such as coronary artery bypass grafting and peripheral artery bypass grafting. Currently, autologous vessels such as the saphenous vein and internal thoracic artery represent the gold standard grafts for small-diameter vessels (<6 mm), outperforming synthetic alternatives. However, these vessels are of limited availability, require invasive harvest, and are often unsuitable for use. To address this, the development of a tissue-engineered vascular graft (TEVG) has been rigorously pursued. This article reviews the current state of the art of TEVGs. The various approaches being explored to generate TEVGs are described, including scaffold-based methods (using synthetic and natural polymers), the use of decellularized natural matrices, and tissue self-assembly processes, with the results of various in vivo studies, including clinical trials, highlighted. A discussion of the key areas for further investigation, including graft cell source, mechanical properties, hemodynamics, integration, and assessment in animal models, is then presented.

Brilliant blue FCF as an alternative dye for saphenous vein graft marking: effect on conduit function.

Surgical skin markers are used off-label to mark human saphenous veins (HSVs) to maintain orientation before implantation as aortocoronary or peripheral arterial bypass grafts. These surgical skin markers impair functional responses of the HSV tissue. To investigate the effect of brilliant blue dye 1 (brilliant blue FCF [for food coloring]; hereinafter, FCF) as a nontoxic alternative marking dye and to determine whether FCF has pharmacological properties. Segments of HSVs were collected in university hospitals from patients undergoing coronary artery bypass grafting procedures immediately after harvest (unmanipulated) or after typical intraoperative surgical graft preparation (after manipulation). Rat inferior venae cavae were used to determine the pharmacological properties and cellular targets of FCF. Endothelial and smooth muscle functional responses were determined in a muscle bath, and intimal thickening in HSVs was determined after 14 days in organ culture. Contractile responses were measured in force and converted to stress. Smooth muscle function was expressed as maximal responses to potassium chloride depolarization contractions. Endothelial function was defined as the percentage of relaxation of maximal agonist-induced contraction. Neointimal thickness was measured by histomorphometric analysis. Human saphenous veins stored in the presence of FCF had no loss of endothelial or smooth muscle function. Unmanipulated HSVs preserved in the presence of FCF demonstrated a significant increase in endothelial-dependent relaxation (mean [SEM], 25.2% [6.4%] vs 30.2% [6.7%]; P = .02). Application of FCF to functionally nonviable tissue significantly enhanced the smooth muscle responses (mean [SEM], 0.018 [0.004] × 10⁵ N/m² vs 0.057 [0.016] × 10⁵ N/m²; P = .05). Treatment with FCF reduced intimal thickness in organ culture (mean [SEM], -17.5% [2.1%] for unmanipulated HSVs vs -27.9% [3.7%] for HSVs after manipulation; P < .001). In rat inferior venae cavae, FCF inhibited the contraction induced by the P2X7 receptor agonist 2'(3')-O-(4-benzoyl)benzoyl-adenosine-5'-triphosphate (mean [SEM], 14.8% [2.2%] vs 6.5% [1.8%]; P = .02) to an extent similar to the P2X7 receptor antagonist oxidized adenosine triphosphate (mean [SEM], 5.0% [0.9%]; P < .02 vs control) or the pannexin hemichannel inhibitor probenecid (mean [SEM], 7.3% [1.6%] and 4.7% [0.9%] for 0.5mM and 2mM, respectively; P < .05). Treatment with FCF did not impair endothelial or smooth muscle function in HSVs. Brilliant blue FCF enhanced endothelial-dependent relaxation, restored smooth muscle function, and prevented intimal hyperplasia in HSVs in organ culture. These pharmacological properties of FCF may be due to P2X7 receptor or pannexin channel inhibition. Brilliant blue FCF is an alternative, nontoxic marking dye that may improve HSV conduit function and decrease intimal hyperplasia.

Duplex ultrasound for the detection of stenosis after peripheral arterial bypass grafting using autologous vein

Duplex ultrasound for the detection of stenosis after peripheral arterial bypass grafting using autologous vein

Homocysteine lowering interventions for peripheral arterial disease and bypass grafts

Elevated plasma levels of the amino acid homocysteine (hyperhomocysteinaemia) are associated with narrowing or blocking of the arteries (atherosclerosis). Treatment to lower homocysteine levels has been shown to be both effective and cheap in healthy volunteers. However, the impact of reducing homocysteine levels on the progression of atherosclerosis and patency of the vessels after treatment for atherosclerosis is still unknown and forms the basis for this review. This is the second update of a review first published in 2002. To assess the effects of plasma homocysteine lowering therapy on the clinical progression of disease in people with peripheral arterial disease (PAD) and hyperhomocysteinaemia including, as a subset, those who have undergone surgical or radiological intervention. For this update, the Cochrane Peripheral Vascular Disease Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched January 2013) and CENTRAL (2012, Issue 12). Trial databases were searched by the TSC (January 2013) for details of ongoing and unpublished studies. We also searched the reference lists of relevant articles. Randomised trials in which participants with PAD and hyperhomocysteinaemia were allocated to either homocysteine lowering therapy or no treatment, including participants before and after surgical or radiological interventions. Two review authors independently assessed trial quality and extracted the data. Information on adverse events was collected from the trials. Two randomised trials with a total of 161 participants were included in this review. The studies did not report on mortality and rate of limb loss. One randomised trial with a total of 133 participants showed that there was a significant improvement in ankle brachial index (ABI) in participants who received folic acid compared with placebo (mean difference (MD) 0.07, 95% confidence interval (CI) 0.04 to 0.11, P < 0.001) and in participants who received 5-methyltetrahydrofolate (5-MTHF) versus placebo (MD 0.05, 95% CI 0.01 to 0.10, P = 0.009). A second trial with a total of 18 participants showed that there was no difference (P non-significant) in ABI in participants who received a multivitamin B supplement (mean ± SEM: 0.7 ± 01) compared with placebo (mean ± SEM: 0.8 ± 0.1). No major events were reported. Currently, no recommendation can be made regarding the value of treatment of hyperhomocysteinaemia in peripheral arterial disease. Further, well constructed trials are urgently required.

A randomized controlled trial comparing an intraoperative goal-directed strategy with routine clinical practice in patients undergoing peripheral arterial surgery

We hypothesized that, in vascular surgery patients, the application of a goal-directed strategy based on a pulse contour-derived cardiac index would be associated with a better haemodynamic status than the application of routine perioperative care and that the amount of fluid and/or inotropes required in such a goal-directed therapy depended on the general anaesthetic technique used. Patients undergoing peripheral arterial bypass grafting were randomly assigned to three groups. In group 1, haemodynamic management was performed according to routine clinical practice. In the two other groups (groups 2 and 3) a goal-directed therapy was applied aiming to maintain the pulse contour-derived cardiac index above 2.5 l m min. Patients in groups 1 and 2 received sevoflurane-based anaesthesia and patients in group 3 propofol-based anaesthesia. Haemodynamic variables, amount of fluid and administration of inotropes were assessed at different time intervals. The amount of fluid administered was not significantly different between the groups. Two patients in group 1, 13 patients in group 2 and 12 patients in group 3 were treated with dobutamine (P < 0.001). None of the patients anaesthetized with sevoflurane (groups 1 and 2) experienced postoperative cardiovascular complications, whereas four patients in the total intravenous group (group 3) experienced major postoperative cardiovascular complications (P = 0.005). In the conditions of the present study, the application of a goal-directed therapy aiming to maintain the cardiac index above 2.5 l min m did not result in a higher tissue oxygen delivery than when applying the standard haemodynamic strategy nor did it depend on the anaesthetic technique used.

Use of an autologous artery for tibial artery bypass in a trauma patient

Peripheral artery bypass grafting is a commonly performed procedure. The present report describes the use of an autologous artery for tibial artery bypass graft following a gunshot wound to the calf. Approximately 4 cm of proximal peroneal artery was harvested for use as a bypass graft. At one year postoperatively, an arterial duplex scan showed patency of the tibioperoneal trunk to the posterior artery bypass.

Rolling autogenetic dermis up to form a tube may be used as scaffold in tissue-engineered blood vessels

Coronary and peripheral artery bypass grafting are widely being used to deal with vascular deficiencies currently, and a man-made synthetic tube or autogenous arteries or veins are needed a lot. But one's autogenous arteries or veins are limited, and artificial graft substitute isn't yet available in clinical applications because of many disadvantages. Various polymeric materials have been used as scaffolds, but without satisfying results due to intimal hyperplasia and the rate of degradation. Autogenetic dermis, which has the advantages of resistance to immunogenicity, good biocompatibility, and appropriate mechanical and physiological properties, has gained our attention to use it as a scaffold for tissue-engineered blood vessels. What is more, autogenetic dermis can be harvested easily. So we postulate that autogenetic dermis rolled up to form a tube may be an ideal scaffold for tissue-engineered blood vessels.

Is Balloon Angioplasty of Peri-Anastomotic Stenoses of Failing Peripheral Arterial Bypasses Worthwhile?

Surgical revision of failing peripheral arterial bypass grafts has generally been shown to provide superior patency rates compared to balloon angioplasty. We analyzed whether balloon angioplasty, specifically of peri-anastomotic stenoses (PAS), provided acceptable patency rates, because surgery for these lesions is more difficult and is likely associated with higher complication rates compared to surgical revision of stenoses in the body of a graft. This is a retrospective review of PAS balloon angioplasties performed at a single institution between January 1, 1999, and September 1, 2005. We report ''primary site patency'' as a stenosis treated by balloon angioplasty, ''revised primary site patency'' as a stenosis treated by repeat balloon angioplasty, and ''secondary site patency'' as an angioplastied stenosis treated surgically or when the graft thrombosed and was revised surgically. All procedures were performed in an endovascular operating room based on duplex scan findings suggesting a significant stenosis. 48 PAS in 33 autologous vein and 15 prosthetic grafts were treated by balloon angioplasty in 42 patients. Mean follow-up was 12 months (range, 1-49 months). Interventions were performed on 22 femoropopliteal grafts (11 proximal, 11 distal), 20 femorotibial grafts (5 proximal, 15 distal), 2 axillofemoral grafts (2 proximal anastomoses), 2 popliteal-pedal grafts (1 proximal, 1 distal), and 1 common iliac-femoral graft (proximal). Life-table analysis revealed 2-year primary, assisted primary, and secondary patency rates of 38%, 58%, and 84%, respectively. No major complications occurred with any endovascular intervention. Balloon angioplasty of PAS resulted in acceptable 2-year assisted primary patency rate of almost 60%. Endovascular intervention avoided repeat incisions in scarred groins, higher rates of nerve injury and infection, significant blood loss, and longer length of hospital stays. We recommend that balloon angioplasty of PAS be attempted before resorting to surgical intervention, especially in cases of hostile anastomotic wounds.

A comparison of recombinant thrombin to bovine thrombin as a hemostatic ancillary in patients undergoing peripheral arterial bypass and arteriovenous graft procedures

A comparison of recombinant thrombin to bovine thrombin as a hemostatic ancillary in patients undergoing peripheral arterial bypass and arteriovenous graft procedures

A comparison of recombinant thrombin to bovine thrombin as a hemostatic ancillary in patients undergoing peripheral arterial bypass and arteriovenous graft procedures

A comparison of recombinant thrombin to bovine thrombin as a hemostatic ancillary in patients undergoing peripheral arterial bypass and arteriovenous graft procedures

Treatment of anastomotic stenoses of peripheral bypass grafts with cutting balloon angioplasty

The aim of this study was to assess the efficacy of cutting-balloon angioplasty (CBA) in the treatment of anastomotic stenoses of peripheral arterial bypass grafts. Seventeen patients (12 men and five women; age range 54-79 years, mean age 66.5) with stenosis or occlusion at the proximal or distal anastomoses of peripheral bypass grafts were treated with CBA. The diagnosis of stenosis was based on clinical and colour-Doppler ultrasound findings and confirmed by angiography with measurement of the intraluminal transstenotic pressure gradients. The diameter of the selected cutting balloon was 1-mm smaller than the vessel distal to the anastomosis and, in the event of suboptimal outcome, the procedure was completed with repeat dilatation with a larger standard balloon (+1 mm). Technical success was obtained in 100% of cases. In three patients, CBA was performed after locoregional thrombolysis. No patient required stent placement or emergency surgery due to the presence of residual stenosis, suboptimal outcome or dissection. No complication occurred either during or after the procedure. During a mean follow-up period of 10.4 months (range 5-21 months), two restenoses developed at 9 and 7 months, which were treated with the same technique; in one patient with recurrent bypass occlusion at 5 months, a new bypass was created surgically owing to contraindications for locoregional thrombolysis. Cumulative primary patency at 12 and 18 months was 82.35%, whereas the two cases of restenoses treated with repeat CBA underwent further follow-up at 10 and 7 months, respectively. Our data confirm the efficacy of CBA in the treatment of anastomotic stenoses of peripheral arterial bypass grafts.

A comparison of recombinant thrombin to bovine thrombin as a hemostatic ancillary in patients undergoing peripheral arterial bypass and arteriovenous graft procedures

Recombinant thrombin (rThrombin) is a potential hemostatic alternative to bovine and human plasma-derived thrombin. This report examines the clinical results for the vascular surgery subgroup of patients enrolled in a larger double-blind, randomized, multicenter trial, which evaluated the comparative safety and efficacy of rThrombin and bovine plasma-derived thrombin (bThrombin) when used as adjuncts to surgical hemostasis. Data from the 164 vascular patients who underwent either a peripheral arterial bypass (PAB) or arteriovenous graft (AV) procedure are included in this analysis. Time to hemostasis at proximal and distal anastomotic sites at 1.5-, 3-, 6-, and 10-minute intervals was determined by procedure (PAB or AV) and overall (PAB + AV). Baseline and day 29 immunologic sera were analyzed. The incidences of postoperative adverse events were compared between treatment groups. Categorical adverse events were evaluated in relation to thrombin product antibody formation. Patients were randomized to either bThrombin (n = 82) or rThrombin (n = 82). Procedures included PAB (n = 88) and AV (n = 76). The bThrombin and rThrombin groups were well matched for demographics and baseline characteristics. A comparable incidence of anastomotic hemostasis was observed in both treatment groups at 10 minutes (94% bThrombin, 91% rThrombin). The incidence of hemostasis was lower at all time points for PAB procedures compared with AV procedures. In the PAB group, a significantly greater proportion of patients receiving rThrombin (55%) achieved hemostasis at 3 minutes compared with bThrombin (39%; P < .05). Adverse event profiles and laboratory findings were similar between groups. No patients in the rThrombin group developed anti-rThrombin product antibodies at day 29, whereas 27% of patients in the bThrombin group developed antibodies to bThrombin product (P < .0001). rThrombin or bThrombin used as a hemostatic ancillary for anastomotic bleeding was equally effective at 10 minutes; however, rThrombin compared with bThrombin may provide a more rapid onset of hemostasis at 3 minutes in PAB procedures. Adverse events were similar between the two thrombins. In patients undergoing vascular surgery, both treatments were similarly well tolerated, although rThrombin demonstrated a superior immunogenicity profile.

Increased Neointimal Formation After Surgical Vein Grafting in a Murine Model of Type 2 Diabetes

Diabetes is an independent risk factor for the development of neointimal hyperplasia and subsequent vein graft failure after coronary or peripheral artery bypass grafting. We evaluate a new mouse model of surgical vein grafting to investigate the mechanisms of neointimal formation in the setting of type 2 diabetes. Surgical vein grafts were created by inserting vein segments from age-matched C57BL/KsJ wild-type mice into the infra-renal aorta of lepr(db/db) diabetic and C57BL/KsJ wild-type mice. Mice were euthanized &4 weeks later, and vein grafts were analyzed using morphometric and immunohistochemical techniques. A significant increase in neointimal formation was noted in lepr(db/db) mice (139+/-64 versus 109+/-62 mm2; P=0.008) after 4 weeks. This difference was mainly secondary to an increase in collagen formation within the lesion in the vein grafts from lepr(db/db) mice (0.53+/-0.4 versus 0.44+/-0.05; P<0.001), whereas only slight increases (P=not significant) in alpha actin-stained smooth muscle cells were noted in the lepr(db/db) mice. We established a new physiologically relevant model of surgical vein grafting in mice. In this report, type 2 diabetes was associated with significant increase in extracellular matrix deposition in addition to increased smooth muscle cell deposition. This new model may allow mechanistic studies of cellular and molecular pathways of increased neointimal formation in the setting of diabetes.